fix(v4): the final review's six minors in the ROM boot

- Text after start is refused, as text.c refuses it: before it jumps, the
  ROM reads on to the end of the source; blanks, comments and the ends of
  blobs may follow, a token is ERR-AFTER (26), "text after start".
- A token too long where a name, a target or a value is wanted is "name
  too long", as text.c says: (MISSING) reports "missing" only when no error
  came first.  `", keeps "missing", which is text.c's word for both.
- text.c's "address out of range" names the address, not the value.
- The system's source files are one list, v4/sys_files.h: boot.c, the
  harness and the nucleus test are made from it.
- The ROM's error codes and words are one list, v4/rom_errors.h: boot.c's
  messages, host_map.h's ROM_ERR_* and mkmap's ERR-* are made from it.
- node.h says what v4_node_store does with a ROM address (nothing, as for
  any address outside RAM, D-14); test_host_rom_range pins it.

ROM: 2095 words, rom_hash 0x06d0dcb7a0cb41a1.  dict_hash unchanged,
0xe5a57f3eb72ff94a.  make -C v4 test test-32 hosted-check pass.  QEMU:
amd64, aarch64, riscv64 to ok>, POST 538/538, POST: PASSED.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

v4/tests/test_host_rom_range.c

@@ -46,6 +46,8 @@ int main(void)
     v4_node_rom_attach(&n, rom, 16);
     CHECK(v4_node_load(&n, V4_ROM_BASE) == rom[0], "the ROM reads");
     CHECK(v4_node_load(&n, V4_ROM_BASE + 16) == 0, "past the ROM's words: nothing");
+    v4_node_store(&n, V4_ROM_BASE, 12345);
+    CHECK(v4_node_load(&n, V4_ROM_BASE) == rom[0] && n.faults == 0, "C code's store into the ROM does nothing and counts no fault (node.h)");
 
     /* RAM 16: call the ROM's word, then return */
     v4_asm_begin(&as, &n, 16);